Python - Converting a Number to a Letter without an if statement - python

I am making a program for my own purposes (a naming program) that completely generates a random name. The problem is I cannot assign a number to a letter, so as a being 1 and z being 26, or a being 0 and z being 25. It gives me a SyntaxError. I need to assign this because the random integer (1,26) triggers a letter (if the random integer is 1, select A) and prints the name.
EDIT:
I have implemented your advice, and it works, I am grateful for this, but I wish to have my program create readable names, or more procedural. Here is an example of a name after I tweaked my program: ddjau. Now that doesn't look like a name, so I want it my program to work as if it were creating REAL names, like Samuel or other common names. Thanks!
EDIT (2):
Thanks, Adam, but I need a sort of 'seed' for the user to enter for the start of the name is. (Seed = A, Name = Adam. Seed = G, Name = George.) Should I do this by searching the file line by line, at the very beginning? If so, how do I do this?

Short Answer
Look into Python dictionaries to allow the 1 = 'a' type assignments. Below I have working example that would generate a random name based on gender and a 'litter'.
Disclaimer
I do not fully understand (via the code) what you're trying to accomplish with char/ord and a random letter. Also note having absolutely no idea of your design goals or requirements, I have made the example more complex than it may need to be for instructional purposes.
Additional Resources
* Python Docs for dictionary
* Using Python dictionary relationship to search both ways
In response to the last edit
If you are looking to build random 'real' names, I think your best bet will be to use a large list of names and just pick a random one. If I were you I'd look into something linking to the census results: males and females. Note that male_names.txt and female_names.txt are a copy of the list found at the census website. As a disclaimer, I'm sure there is a more efficient way to load / read the file. Just use this example as a proof on concept.
Update
Here's a quick and dirty way to seed the random values. Again I am not sure that this is the most pythonic way or most efficient way, but it works.
Example
import random
import time
def get_random_name(gender, seed):
if(gender == 'male'):
file = 'male_names.txt'
elif(gender == 'female'):
file = 'female_names.txt'
fid = open(file,'r')
names = []
total_names = 0
for line in fid:
if(line.lower().startswith(seed)):
names.append(line)
total_names = total_names + 1
random_index = random.randint(0,total_names)
return names[random_index]
if (__name__ == "__main__"):
print 'Welcome to Name Database 2.2\n'
print '1. Boy'
print '2. Girl'
bog = raw_input('\nGender: ')
print 'What should the name start with?'
print 'A, Ab, Abc, B, Ba, Br, etc...'
print ''
l = raw_input('Leter(s): ').lower()
new_name = ''
if bog == '1': # Boy
print get_random_name('male',l)
elif bog == '2':
print get_random_name('female',l)
Output
Welcome to Name Database 2.2
1. Boy
2. Girl
Gender: 2
What should the name start with?
A, Ab, Abc, B, Ba, Br, etc...
Leter(s): br
BRITTA

chr (see here) and ord (see here) are the two functions you're looking for (though you already seem to know about the latter). Follow those links for a more detailed explanation.
The first gives you a one-character string based on the integer, the second does the reverse operaion (technically, it handles Unicode as well, which chr doesn't, though you have unichr for that if you need it).
You can base your code on the following:
ch = "E"
print ord (ch) - ord ("A") + 1 # should give 5 for the fifth letter
val = 7
print chr (val + ord ("A") - 1) # should give G, the seventh letter

I'm not entirely sure what you're trying to do, but you can convert a number into a letter with the chr() function. chr() takes an ASCII code, so if you want to use the range [0, 25] instead you can adapt it like so:
chr(25 + ord('a')) # 'z'

Related

How do I solve my program's counting problem?

(Apologies this is gonna be a long question)
I just have a bug in my code that I have not been able to resolve for a very long time. I would really appreciate if someone could help me find out what the problem is.
Context:
I have a long string of letters - lets call this subject - containing the letters A, G, T and C (like DNA) and the whole point of my algorithms is to correctly count how many of each of the following STRs are found within subject. The STRs are:
AGATC
TTTTTTCT
AATG
TCTAG
GATA
TATC
GAAA
TCTG
I must count how many of each are within subject. Counting works by going sequentially letter by letter until the start of one of above STRs are found. If the rest of the STR follows, the program should update the counter of the respective STR and then boost the searching index to account of the length of the STR and then keep going. It should stop when it reaches the end of subject.
(Hope it makes sense).
My Code:
STRs = ['AGATC','TTTTTTCT','AATG','TCTAG','GATA','TATC','GAAA','TCTG']
subject = "GCTAAATTTGTTCAGCCAGATGTAGGCTTACAAATCAAGCTGTCCGCTCGGCACGGCCTACACACGTCGTGTAACTACAACAGCTAGTTAATCTGGATATCACCATGACCGAATCATAGATTTCGCCTTAAGGAGCTTTACCATGGCTTGGGATCCAATACTAAGGGCTCGACCTAGGCGAATGAGTTTCAGGTTGGCAATCAGCAACGCTCGCCATCCGGACGACGGCTTACAGTTAGTAGCATAGTACGCGATTTTCGGGAAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGAATGTATCTATCTATCTATCTATCTATCTATCTATCTATCTATCTATCTATCTATCTATCTATCTATCTATCTATCCCGTCAACTCATTCACACCGCATCCTTTCCTGCCACTGTAACTAGTCGACTGGGGAACCTCATCATCCATACTCTCCCACATTATGCCTCCCAACCTTGTTAAGCGTGGCATGCTTGGGATTGCATTGATGCTTCTTGGAGAGGACGCTTTCGTTTTGGAGATTACAGGGATCCAATTTTATCATCGGTTCGACTCCCGTAACGACTTAGCAGTAAGGGTGCTAGTTCCTGGTTAGAATCTTAATAAATCACGTCGCTTGGAGCAAGACAAAGATCGTCGTAATGCCAAGTGCACGACCACCTTCAGACTTGCAGGACCCGTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTTTTTTTCTCGATAGCTATGCGGTTCAATACAATCTTAACGCAATGCAGCGATGTGGTTTCGTACACTTAGCATAAAACCCCCCACATTAAATCGATGTACCCGCCCTCTTAGACGCCAATTTCAATGCCGAACCTCCGGCGGGTATCTCTGCACTAGGAGAAGTAGCACGTCGCTGTAGCGAACTCCTATCGTGAGATAATTTGTAGAGCTGCTCTTATAATACAATAGCTCAGATGGATTATTCCATGGACATCCCCGTGCGTTGTTTCGAGGATGGTAGGTGGAAATTTTGCCAGACCTCTAGTCTTAAACATGGTTGACGTTATAGGCGCTATCTCTTGCGTCTGGAAGTGTTAATCCGTGAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAAGAAACACGCAACTCTGGAGGAGGGCACTGCACTGCAAACTTGCGTAATATCCTTCACCCACACTTGCCTGGCCTCCTTGCTTAAAGCTCTGGCGATGCGATTTTTCGGCCCAGTAGCTGAATAGGTCATGAAATGGGCACCGAACTGGAAAGACCCATATATTCGATACTCACAACTTAATGATAGCGCGATTAAGAGCGACACCAAAAACCAAATTACGTTCACGAACCTTTGAGAGTCAAGGAGACTTAGACCGAATTGAATGATCACTGATGCGCCCGCTGATACTGAGCCTCACCATTAATCGCCGACCAATACGGCGTGTACCGGGCGCGGCCTTGCCGCATAACGATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATATCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTCTGTACACAGCCCCGTCCTCATTGCTAAGTGCACTGGCAACTGGACCTAAAGATTTTTCGAGTATGGCCCTCGAATCAAGCGCCCACCCAGAAACCTACGAGCCAGTAACCCCAGTAAACAAGCATTAGTGCTATATGCTTGCTGCCCACTAGGACCCTTATGGTTCATACCAGGGTGACGTGTCTTGCGGGCCAAGGATGAACCAGAAGCAAGATCCTTAGATGGACGACTGTCTCATTGCTTAAACTCCACATACCAAAGGGCGCGGTAAACGATAGTTTTAGGTAATGTTAGTCGGATGGTTGTCTGCAGCTACCAATACAGCCTGGCACCCAGGGTCTGAACAATAACGCGTGAGAGCAGCTCTCCCGCGTGTGGTGGATTTGCCGTCTATGAAATTGAGGCTCTTGCAACTATTCGCACTCGGAATGCCCTCATATCTGGTGCCTAGCGGCCTTTGCCCCGTGCCGGTAGGACTAAACTCTACGGATCGTTGACGGATCTCGATGTGGAAGATGGTTATGAAAGATAACAACGCGTGTGCTAATTGATTTAGACAAGTATTGCGGCAGTAAAAGATAATCGGCTGCAGAGTTACGAAAGACTTCCATGCATGGATTCCATTCCTTCTAGTATAGGACCCACTCTGAATACACGTCTTGCGGGCCGATCATCTCCACCGCTGCGGAAGAAAGCAATTAAGAATCTATGCTCATTAAGAGTGCGACTATAATGCGGATCTTACAGTGCTAATGATCAGGACGTCGTCCAAGCAGGCTGCATGCCGAATTTAGCTTACGTCAGGATCAGGCGTTATAGCCTGGGAATCGGACTATGAGGACGCCACGACCTCTGGGAGAAAGCTATATACATTGAGGATCGCGCCATCTTTATGAGACTCAAATGAATCTAGATAGGTAGCATTGCGGACTTGAGTTAGCACATCGGTATTGGAAGGTGAGGGTCCTGCCGCTCGTTCTATGTTCGGTTTATAGTATACAAATAGGTCATCCCGAACGTTGAAGTTAAACTCATGACACGTTGTCGTAATGAAACGGGCCTGTTATTAGGGATACAGACAAAAGGCACAAGCTGGCTTGCACATTAAGGCGCACTAGAGATCCTCACAACCGTTGCCCGCACGGAGGTCGTGTCTAACAGACAGTGAACCAGCCGTATTGGGGTGGATGACCTGAGCTTCTTGGGGCCTGTTGTACACCGCGTGTGGTTCAACTGGTACACATACTACGAATATTCGAAATCATTGTACTGTGCTCTTCGGTGCTACTGACTGTGAGCGAATGCATCCCAATCCCAAACAATGCTTGTGGTAGGAGAATTGAAACTCTCGAAGCCTGGCCCAATGTCATCTACTTTTAACATGTCGGGCCAGGAGTTACGGGCATTGCTTACTTACTTTGCCCCCTTACACCACAGCAGCGCGATTCTTGTTGTAGTAGATTTTATACGACTCGCGAATTAAATGGAACTTGTCTGTCCCATATCGATCGTGTCCATCGTAAGATGAGATTGTAGGAGCATTCGGAAGTCTATGCGGCCCAGGGACTACTACGTTAAATCTGGTCAGACGTGGTTTACAAGGCGTCCCGATCTTCTCAGAACATATGGGAAAGCACTACCGTTCCTTCACGCATACAGTTGTTCGTGCCGAACGAGTAAGCTTGCGACCAGCCCACCCGCTAGGGCTATGCAGCGGGTCATGGCTGGCGCCATACTGTGCGGACAACCCACGCTCTGGCAGAAAGCGTCTTGTGTTTTGTAGTAGCTCCAACGGTTAGACCTTCGATATCTATTCAGAGCGCGAGCGACCACTATTAGACGGCATGTAAACAATGTGTATTTGTTCGGCCCAACCGGTATATGGGTAAGACCGCGAAGGGCCTGCGCGAATACCAGCGTCCAAAAATTCCTCACCCGAGATATGCGGTTAGTACCCCTTGGGTAACGGTCCGCTACGGGTAGCGACGCGAGCCGGCCGCATCGGTTGGAGCCGAGTTGTCGGGCAGGCGAGTAACGTGTGCAATTTGATGGGCCCAAGCCTCCGGCACTATCCACCTCATACATCGACAAAAGCACCAAATATGGGGAAAAGCTGAGCGTCGATATGTACATCTACCCAGGAACCGGCCCGAACATTAGGCGGACGTGAATTTCCGACCTAGGTTCGGCTACATTTCTACGATCCAAGCACACGTGAAGGAGGAGGGGTGTTCCGACCGTAAATGAACGAGGTGCGCAGTGACCCGATGGCGTTTAGCGGATAGCCTTCCTATGCCGGCCTATGCTGTATGGTAGTTGGTTGGTGCCTCCAGAGCCACTGCACCCAATCATAGGGTCTACAGCAGCGTACTTATAAAATTGTACGGGTGACCCATATCCATTACGGGTTGCGACCAGTATAGGAGAGTATAACTGCGTGAACTAATGCGTTATGACGCTTCAGAGTTTGCTCGGGCCCGAGTTCTAGGGCTATAATGTGTTAGGGCGCAAGTATGCCAAGCTAAGATGTGGCGTGCACACTAGGAGTTGTGTTCCTCTGCAAGCAGACACGAGCACTCTGGCAGTAGTTTGACCACACCCGGGTATCACTGCTACTCCATTTCGAACAAGCTATTGGAGCGGACAAAATATGCTACTCAAGAGCATTAGTTATAGGTCTACGAGACAGAAGCAGTTACTGAGTCTGAATATTCGATATAAGTAGGCATGGAGGCGGAGCAAAACAACGTCTGCGATCAATCGTGTTGATGACGTATGGCGACTGGAAGGTAAGGACTATGGCCGGACGGAATGATTCATGTTCTGTTCAAAGCTATATTTCGAAGGGGTATATTAGCGGTCCTACACTTGGTTAGCACCCTCCCCCCTCTGGATCCTGCACTAATTCGAGCTGGCCTCCATCGGTATCAGTCCGGAAGCTCCACTCTCTATCGTAGTCCTAATCAACAGGGTGCCAGTTTGCTCACGTGGAAGTTTGAGGCCCTTTGTGCTCCATAGCCAATCACTAACCATGCACGCGCGACCCACTCTACGTCCAGATCGGCTATAATAGTTGCGCCCGGGACTGGCAGAGTAGACATGTAAGCTAGATAGAGCCCCGACATCGGCCAAGAGATCCTACGCTGCTTCCAGATAATGAGAGACATTCTAGCATTAGACATGCAAGTCGGCAGGGACTCCCCTTATCTAGTAATTTCGATGAATTGGTTTTTCGGCTAGCATCTAGTCTAGTCTAGTCTAGTCTAGTCTAGTCTAGTCTAGTCTAGTCTAGTCTAGTCTAGACCATGCCGACCTCATCATAGAAGGAATGCTCTAAACTTAGAGTGCTACTAGGAAAACTATTAATCAATGATCGTCCTGCTTACATAGCTGGACGGCGAAAGTTCTTATACTGCGGAGGTTGCTGACGTAGAGTGCGCTGGGTACAGCGGATAAGTTGATCAGGGTGGGGATAGGGTGGCTCACCGTTTATACTCATATAGATTCCTGGCGTCGACGCTGTGACAGGGTCGAGATCGAGGGGGAGATCAGATCAGATCAGATCAGATCAGATCAGATCAGATCAGATCAGATCAGATCAGATCAGATCAGATCAGATCAGATCAGATCAGATCAGATCAGATCAGATCAGATCAGCGGAGCGGAGGGAAAATTATCACCAGAGGGTAGGGGCTCGCGACATTCTATTCAATGCATTTCAAGCTACTTACGTATTTCGGCACAGTGACTACTGCCTGCGCGGCAGCCGTAAGGTTTCCCGTCAATAGGTGGCACGTATCATTGATGAAAGTGTCAGCTAATCATTCAGGCCTTA"
x = 0 # Searching index.
dataSTR = { # All the STRs to seach for.
"AGATC":0,
"TTTTTTCT":0,
"AATG":0,
"TCTAG":0,
"GATA":0,
"TATC":0,
"GAAA":0,
"TCTG":0,
}
# This dict will hold all the count values of STR's in the text-file.
# Scanning STR's from the txt file.
total = len(subject)
limit = 8
while x < total:
currentString = subject[x:x+limit] # A temporary variable to hold the next few letters from the text-file at index x.
for STR in STRs:
if STR in currentString: # The STR is found within this set of letters?
lSTR = len(STR) - 1
if STR[0:lSTR] == currentString[0:lSTR]: # In order to minimise the risk of duplication...
dataSTR[STR] += 1 # ...the STR must be at the start of currentString.
#print(currentString, STR, x, dataSTR[STR])
x += lSTR # The index must be boosted each time a new STR is read. In the event that an STR is at the end of a stand...
x += 1 # The index counts up by 1 by default. (From above) ...so that no duplicates are added.
print(dataSTR.items())
print("The correct result is: AGATC - 22, TTTTTTCT - 33, AATG - 43, TCTAG - 12, GATA - 26, TATC - 18, GAAA - 47, TCTG - 41")
(Sorry its very long, it might be helpful to copy into a separate python file).
As you will see from running it, the result my program brings up from counting is incorrect. The correct results are in the final print statement of the program, but the program does not match this (yes I know that these results are 100% correct since this is part of a problem set from an online computer science course).
However, I cannot seem to find the bug or logic error that seems to be causing my program to count wrong and I have been trying for quite a while now. Does anyone know what the solution is?
Please feel free to ask me anything about the program, thank you all.
Your problem statement doesn't agree with the "correct results" given in your example code. Either you've misunderstood the problem, or you've taken the correct results from a different problem. (The "correct results" appear to be for the problem of finding the maximum number of consecutive repeats of each query string.) [The latter possibility is the point that Chris Charley makes in a comment on the original post.]
You can convince yourself by doing the problem "by hand": look at the subject string in a text editor, pick a query string, do a search on it, and step through the occurrences.
E.g., for the query string "GAAA", you'll count ~67 occurrences, but most of them are in a block of 47 repeats in subject[1449:1637]. (This is more obvious if you use a text editor that highlights all occurrences of the search string, as 188 characters of consecutive highlighting should jump out at you.) And 47 agrees with the "correct result" for GAAA.
Does this help?
count_results = dict()
STRs = ['AGATC','TTTTTTCT','AATG','TCTAG','GATA','TATC','GAAA','TCTG']
subject = "loooong string..."
for search_string in STRs:
count_results[search_string] = subject.count(search_string)
print(count_results)
{'AGATC': 28, 'TTTTTTCT': 33, 'AATG': 69, 'TCTAG': 18, 'GATA': 46, 'TATC': 36, 'GAAA': 67, 'TCTG': 60}
I realize the results are sometimes different to your expected counts, but I didn't go through the intricacies of your search algo and wonder if the expected output might be wrong? If not, check out the docs for the str.count() function, to see how & why it gets different output, and adapt what it does to your needs.
Try like this:
import re
# Define STRs and subject here
dic = {}
for x in STRs:
tv = len([m.start() for m in re.finditer(x,subject)])
tv += 1
dic[x] = tv
for y in dic.keys():
print(y,dic[y])
The results in the last print statement are incorrect. I checked it with python's built in method .count(), if you are allowed to use this method just use this one instead, but if not, I would recommend to do the following:
total = len(subject)
while x < total:
for STR in STRs:
limit = len(STR)
currentString = subject[x:x+limit]
if STR == currentString:
dataSTR[STR] += 1
x += 1
that way, you set the limit to the string's length so the STR is either exactly the string or not, so you don't have to check for duplicates. I don't know why your code didn't work, but I hope this will help you.

Print variable by input

How to print variable name by input, Example:
a = 1
b = 2
what_variable = input('Which Variable?: ') #User for example introduces 'b'
Console: 2
You can write
print(globals()[what_variable])
but it's not a good approach. Use a dict instead
You can use exec:
var = input('Which Variable?: ')
exec("print(" + var + ")")
Output:
Which Variable?: b
2
>>
Just do the following:
print(eval(input('Which Variable?: ')))
You can also do
print(globals()[input('Which Variable?: ')])
While the other answers seem to address the obvious solution, it's not very 'Pythonic'. The main issues with these is, by far, safety. Let's say that your user inputs apiKey, and you happen to have a variable by that name... let's just say your bank statement is probably looking at a slight increase in magnitude. What most people in these answers don't realise is that using .globals()[input()] is no safer than eval(input()), because, shockingly, people store private info in variables. Alternatively, if it points to a method, e.g
a = print
b = os.system
eval(input())()
I could enter any function name there, and the damage would be done before the second () executes.
Why? Well, let's take a look at how exec and eval work (I won't go into the difference here, see this question for that). All they do is evaluate the string as Python code, and (simplifying here) return the value of the evaluation:
var1 = 3
print(eval("var1"))
# ====is equal to====
var1 = 3
print(var1)
(where var1 as a string obviously comes from the input typed in)
But if someone enters something malicious, this is essentially the basis of an SQL injection:
(where userInput is substituted by a user's input into an input())
userInput = "a + os.system('reboot now')"
print(eval(userInput))
# ====is equal to====
print(a + os.system('shutdown now')
and you suddenly find your computer's off.
Therefore, we'd either use a:
Dictionary (or object): x={a:1, b:2}, then do x[input()]
Array x=[1, 2], then do x[["a", "b"].index(input())]
Simply don't. Find a way to work around it. What's wrong with an if/else set? It's not good practise, because of the safety concerns outlined above. What most people seem to miss about dictionaries (or my array option) is that if you enter a malformed input (i.e not a or b), it would result in either uncaught errors being thrown, or undefineds being thrown around. And if you're going to do input validation, you're using an if statement anyway, so why not do it from the onset?

Python beginner here : TypeError: 'str' object does not support item assignment

I just started programming with python a couple days ago with no prior experience in programming.
I've been following tutorials online and decided to challenge myself by making a hangman-esque game. I'm trying to make it so that a guess replaces the position an alphabet in the hidden word but python is returning this error. Right now the word is called name and the hidden_name are just #'s in the same length.
name = input ("what is your name ::")
hidden_name = ("#" * len(name))
print (hidden_name)
guess = input ("Guess a letter ::")
def guess_update(guess, name, hidden_name):
right = guess in name
i = 0
for c in name:
if c == guess:
hidden_name[i] = c
i += 1
if guess in name:
guess_update(guess, name, hidden_name)
print ("Your progess is ::", hidden_name)
Thanks for helping this newbie out :)
Strings in Python are immutable, so you cannot do this:
hidden_name[i] = c
One option which will achieve the desired effect for your game is:
hidden_name = hidden_name[:i] + c + hidden_name[i+1:]
This works because you are creating a new string using concatenation, and re-assigning the result back to the variable, rather than attempting to edit the existing string.
Strings in python are inmutable, so you cannot change its content.
One solution would be to split the string, change the letter and stick it back together:
splitted = list(hidden_name)
splitted[i] = c
hidden_name = ''.join(splitted)

Python - turn some of the words in list/str to dots. len(list)?

I've started learning Python last week on codecademy and Google etc. but got stuck and couldn't find the answer anywhere so signed up on stackoverflow.com looking for your support.
I'm trying to build a program that only takes first 5 letters of any name and the remainder of the letter(s) to be shows as blank dot(s). e.g.
Adrian: "Adria."
Michael: "Micha.."
Alexander: "Alexa...." etc.
I tried to "fix" it with the "b" variable but that just prints three dots "..." regardless of how long the name is.
This is what I've got so far:
def namecheck():
name = raw_input("Name?")
if len(name) <=5:
print name
else:
if len(name) >5:
name = name[0:5]
b = ("...")
print name + b
namecheck()
I'm a total newbie so I apologise for any wrong spacing here, thank you for your support and patience.
As an alternative to sequence multiplication (one which is somewhat more self-documenting, and hopefully less confusing to maintainers), just use str.ljust to do your padding:
def namecheck():
name = raw_input("Name?")
# Reduce to first five (or less) characters, then pad with .s to original length
# with str.ljust
print name[:5].ljust(len(name), '.')
print name[:5] + '.' * (len(name) - 5) works fine, it's just a bit arcane (and also involves more temporary values, though in practice, the lack of actual method calls makes it faster on CPython).
you can try to use the function replace().
name = 'abcdefg'
name.replace(name[5:], '.' * len(name[5:]))
output: 'abcde..'
name='randy12345'
name.replace(name[5:],'.' * len(name[5:]))
output: 'randy.....'
name[5:] means get all the element starting 6 (5+1 because it start with 0)
'.' * len(name[5:] then this code count it and multiply it by dot
name.replace(name[5:],'.' * len(name[5:])) then use replace function to replace the excess element with dots
The most concise way I can think of:
def namecheck():
name = raw_input("Name?")
print(name[0:5] + '.' * (len(name) - 5))
namecheck()
Try something like this:
def namecheck():
name = raw_input("Name?")
if len(name) <= 5:
print name
else:
print name[0:5] + '.' * (len(name)-5)
namecheck()

Python: creating a dictionary that writes high scores to a file

First: you don't have to code this for me, unless you're a super awesome nice guy. But since you're all great at programming and understand it so much better than me and all, it might just be easier (since it's probably not too many lines of code) than writing paragraph after paragraph trying to make me understand it.
So - I need to make a list of high scores that updates itself upon new entries. So here it goes:
First step - done
I have player-entered input, which has been taken as a data for a few calculations:
import time
import datetime
print "Current time:", time1.strftime("%d.%m.%Y, %H:%M")
time1 = datetime.datetime.now()
a = raw_input("Enter weight: ")
b = raw_input("Enter height: ")
c = a/b
Second step - making high score list
Here, I would need some sort of a dictionary or a thing that would read the previous entries and check if the score (c) is (at least) better than the score of the last one in "high scores", and if it is, it would prompt you to enter your name.
After you entered your name, it would post your name, your a, b, c, and time in a high score list.
This is what I came up with, and it definitely doesn't work:
list = [("CPU", 200, 100, 2, time1)]
player = "CPU"
a = 200
b = 100
c = 2
time1 = "20.12.2012, 21:38"
list.append((player, a, b, c, time1))
list.sort()
import pickle
scores = open("scores", "w")
pickle.dump(list[-5:], scores)
scores.close()
scores = open("scores", "r")
oldscores = pickle.load(scores)
scores.close()
print oldscores()
I know I did something terribly stupid, but anyways, thanks for reading this and I hope you can help me out with this one. :-)
First, don't use list as a variable name. It shadows the built-in list object. Second, avoid using just plain date strings, since it is much easier to work with datetime objects, which support proper comparisons and easy conversions.
Here is a full example of your code, with individual functions to help divide up the steps. I am trying not to use any more advanced modules or functionality, since you are obviously just learning:
import os
import datetime
import cPickle
# just a constants we can use to define our score file location
SCORES_FILE = "scores.pickle"
def get_user_data():
time1 = datetime.datetime.now()
print "Current time:", time1.strftime("%d.%m.%Y, %H:%M")
a = None
while True:
a = raw_input("Enter weight: ")
try:
a = float(a)
except:
continue
else:
break
b = None
while True:
b = raw_input("Enter height: ")
try:
b = float(b)
except:
continue
else:
break
c = a/b
return ['', a, b, c, time1]
def read_high_scores():
# initialize an empty score file if it does
# not exist already, and return an empty list
if not os.path.isfile(SCORES_FILE):
write_high_scores([])
return []
with open(SCORES_FILE, 'r') as f:
scores = cPickle.load(f)
return scores
def write_high_scores(scores):
with open(SCORES_FILE, 'w') as f:
cPickle.dump(scores, f)
def update_scores(newScore, highScores):
# reuse an anonymous function for looking
# up the `c` (4th item) score from the object
key = lambda item: item[3]
# make a local copy of the scores
highScores = highScores[:]
lowest = None
if highScores:
lowest = min(highScores, key=key)
# only add the new score if the high scores
# are empty, or it beats the lowest one
if lowest is None or (newScore[3] > lowest[3]):
newScore[0] = raw_input("Enter name: ")
highScores.append(newScore)
# take only the highest 5 scores and return them
highScores.sort(key=key, reverse=True)
return highScores[:5]
def print_high_scores(scores):
# loop over scores using enumerate to also
# get an int counter for printing
for i, score in enumerate(scores):
name, a, b, c, time1 = score
# #1 50.0 jdi (20.12.2012, 15:02)
print "#%d\t%s\t%s\t(%s)" % \
(i+1, c, name, time1.strftime("%d.%m.%Y, %H:%M"))
def main():
score = get_user_data()
highScores = read_high_scores()
highScores = update_scores(score, highScores)
write_high_scores(highScores)
print_high_scores(highScores)
if __name__ == "__main__":
main()
What it does now is only add new scores if there were no high scores or it beats the lowest. You could modify it to always add a new score if there are less than 5 previous scores, instead of requiring it to beat the lowest one. And then just perform the lowest check after the size of highscores >= 5
The first thing I noticed is that you did not tell list.sort() that the sorting should be based on the last element of each entry. By default, list.sort() will use Python's default sorting order, which will sort entries based on the first element of each entry (i.e. the name), then mode on to the second element, the third element and so on. So, you have to tell list.sort() which item to use for sorting:
from operator import itemgetter
[...]
list.sort(key=itemgetter(3))
This will sort entries based on the item with index 3 in each tuple, i.e. the fourth item.
Also, print oldscores() will definitely not work since oldscores is not a function, hence you cannot call it with the () operator. print oldscores is probably better.
Here are the things I notice.
These lines seem to be in the wrong order:
print "Current time:", time1.strftime("%d.%m.%Y, %H:%M")
time1 = datetime.datetime.now()
When the user enters the height and weight, they are going to be read in as strings, not integers, so you will get a TypeError on this line:
c = a/b
You could solve this by casting a and b to float like so:
a = float(raw_input("Enter weight: "))
But you'll probably need to wrap this in a try/catch block, in case the user puts in garbage, basically anything that can't be cast to a float. Put the whole thing in a while block until they get it right.
So, something like this:
b = None
while b == None:
try:
b = float(raw_input("Enter height: "))
except:
print "Weight should be entered using only digits, like '187'"
So, on to the second part, you shouldn't use list as a variable name, since it's a builtin, I'll use high_scores.
# Add one default entry to the list
high_scores = [("CPU", 200, 100, 2, "20.12.2012, 4:20")]
You say you want to check the player score against the high score, to see if it's best, but if that's the case, why a list? Why not just a single entry? Anyhow, that's confusing me, not sure if you really want a high score list, or just one high score.
So, let's just add the score, no matter what:
Assume you've gotten their name into the name variable.
high_score.append((name, a, b, c, time1))
Then apply the other answer from #Tamás
You definitely don't want a dictionary here. The whole point of a dictionary is to be able to map keys to values, without any sorting. What you want is a sorted list. And you've already got that.
Well, as Tamás points out, you've actually got a list sorted by the player name, not the score. On top of that, you want to sort in downward order, not upward. You could use the decorate-sort-undecorate pattern, or a key function, or whatever, but you need to do something. Also, you've put it in a variable named list, which is a very bad idea, because that's already the name of the list type.
Anyway, you can find out whether to add something into a sorted list, and where to insert it if so, using the bisect module in the standard library. But it's probably simpler to just use something like SortedCollection or blist.
Here's an example:
highscores = SortedCollection(scores, key=lambda x: -x[3])
Now, when you finish the game:
highscores.insert_right((player, a, b, newscore, time1))
del highscores[-1]
That's it. If you were actually not in the top 10, you'll be added at #11, then removed. If you were in the top 10, you'll be added, and the old #10 will now be #11 and be removed.
If you don't want to prepopulate the list with 10 fake scores the way old arcade games used to, just change it to this:
highscores.insert_right((player, a, b, newscore, time1))
del highscores[10:]
Now, if there were already 10 scores, when you get added, #11 will get deleted, but if there were only 3, nothing gets deleted, and now there are 4.
Meanwhile, I'm not sure why you're writing the new scores out to a pickle file, and then reading the same thing back in. You probably want to do the reading before adding the highscore to the list, and then do the writing after adding it.
You also asked how to "beautify the list". Well, there are three sides to that.
First of all, in the code, (player, a, b, c, time1) isn't very meaningful. Giving the variables better names would help, of course, but ultimately you still come down to the fact that when accessing list, you have to do entry[3] to get the score or entry[4] to get the time.
There are at least three ways to solve this:
Store a list (or SortedCollection) of dicts instead of tuples. The code gets a bit more verbose, but a lot more readable. You write {'player': player, 'height': a, 'weight': b, 'score': c, 'time': time1}, and then when accessing the list, you do entry['score'] instead of entry[3].
Use a collection of namedtuples. Now you can actually just insert ScoreEntry(player, a, b, c, time1), or you can insert ScoreEntry(player=player, height=a, weight=b, score=c, time=time1), whichever is more readable in a given case, and they both work the same way. And you can access entry.score or as entry[3], again using whichever is more readable.
Write an explicit class for score entries. This is pretty similar to the previous one, but there's more code to write, and you can't do indexed access anymore, but on the plus side you don't have to understand namedtuple.
Second, if you just print the entries, they look like a mess. The way to deal with that is string formatting. Instead of print scores, you do something like this:
print '\n'.join("{}: height {}, weight {}, score {} at {}".format(entry)
for entry in highscores)
If you're using a class or namedtuple instead of just a tuple, you can even format by name instead of by position, making the code much more readable.
Finally, the highscore file itself is an unreadable mess, because pickle is not meant for human consumption. If you want it to be human-readable, you have to pick a format, and write the code to serialize that format. Fortunately, the CSV format is pretty human-readable, and most of the code is already written for you in the csv module. (You may want to look at the DictReader and DictWriter classes, especially if you want to write a header line. Again, there's the tradeoff of a bit more code for a lot more readability.)

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